/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: AncestorPattern.java,v 1.2.4.1 2005/09/01 09:19:41 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.GOTO;
import com.sun.org.apache.bcel.internal.generic.IFLT;
import com.sun.org.apache.bcel.internal.generic.ILOAD;
import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
import com.sun.org.apache.bcel.internal.generic.ISTORE;
import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Erwin Bolwidt <ejb@klomp.org>
 */
final class AncestorPattern extends RelativePathPattern {

  private final Pattern _left;        // may be null
  private final RelativePathPattern _right;
  private InstructionHandle _loop;

  public AncestorPattern(RelativePathPattern right) {
    this(null, right);
  }

  public AncestorPattern(Pattern left, RelativePathPattern right) {
    _left = left;
    (_right = right).setParent(this);
    if (left != null) {
      left.setParent(this);
    }
  }

  public InstructionHandle getLoopHandle() {
    return _loop;
  }

  public void setParser(Parser parser) {
    super.setParser(parser);
    if (_left != null) {
      _left.setParser(parser);
    }
    _right.setParser(parser);
  }

  public boolean isWildcard() {
    //!!! can be wildcard
    return false;
  }

  public StepPattern getKernelPattern() {
    return _right.getKernelPattern();
  }

  public void reduceKernelPattern() {
    _right.reduceKernelPattern();
  }

  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    if (_left != null) {
      _left.typeCheck(stable);
    }
    return _right.typeCheck(stable);
  }

  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
    InstructionHandle parent;
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

        /*
         * The scope of this local var must be the entire method since
         * a another pattern may decide to jump back into the loop
         */
    final LocalVariableGen local =
        methodGen.addLocalVariable2("app", Util.getJCRefType(NODE_SIG),
            il.getEnd());

    final com.sun.org.apache.bcel.internal.generic.Instruction loadLocal =
        new ILOAD(local.getIndex());
    final com.sun.org.apache.bcel.internal.generic.Instruction storeLocal =
        new ISTORE(local.getIndex());

    if (_right instanceof StepPattern) {
      il.append(DUP);
      il.append(storeLocal);
      _right.translate(classGen, methodGen);
      il.append(methodGen.loadDOM());
      il.append(loadLocal);
    } else {
      _right.translate(classGen, methodGen);

      if (_right instanceof AncestorPattern) {
        il.append(methodGen.loadDOM());
        il.append(SWAP);
      }
    }

    if (_left != null) {
      final int getParent = cpg.addInterfaceMethodref(DOM_INTF,
          GET_PARENT,
          GET_PARENT_SIG);
      parent = il.append(new INVOKEINTERFACE(getParent, 2));

      il.append(DUP);
      il.append(storeLocal);
      _falseList.add(il.append(new IFLT(null)));
      il.append(loadLocal);

      _left.translate(classGen, methodGen);

      final SyntaxTreeNode p = getParent();
      if (p == null || p instanceof Instruction ||
          p instanceof TopLevelElement) {
        // do nothing
      } else {
        il.append(loadLocal);
      }

      final BranchHandle exit = il.append(new GOTO(null));
      _loop = il.append(methodGen.loadDOM());
      il.append(loadLocal);
      local.setEnd(_loop);
      il.append(new GOTO(parent));
      exit.setTarget(il.append(NOP));
      _left.backPatchFalseList(_loop);

      _trueList.append(_left._trueList);
    } else {
      il.append(POP2);
    }

        /*
         * If _right is an ancestor pattern, backpatch this pattern's false
         * list to the loop that searches for more ancestors.
         */
    if (_right instanceof AncestorPattern) {
      final AncestorPattern ancestor = (AncestorPattern) _right;
      _falseList.backPatch(ancestor.getLoopHandle());    // clears list
    }

    _trueList.append(_right._trueList);
    _falseList.append(_right._falseList);
  }

  public String toString() {
    return "AncestorPattern(" + _left + ", " + _right + ')';
  }
}
